Carrageenan-inflamed muscle. Representative H&E sections were obtained 2 days after carrageenan injection. A-C, H&E sections from ASIC3+/+ mice. A, Carrageenan-inflamed ASIC3+/+ muscle. Carrageenan filled in the intercellular matrix, causing inflammation. B, Vasculitis in carrageenan-inflamed ASIC3+/+ muscle. The arterial wall (right) was intact, but the vein (left) showed vasculitis. C, Higher magnitude of bracket area from B. Black granules were deposited on the vascular wall (arrows) and the lining of the lumen was incomplete. D-F, H&E sections from ASIC3-/- mice. D, Carrageenan-inflamed ASIC3-/- muscle. E, Vein (right) and artery (left) remained integrated in carrageenan-inflamed ASIC3-/- muscle. F, Higher magnitude of bracket area from E.